Railway-traffic-controlling apparatus



Nov. 20, 1928. 1,692,061 7. H. A. THOMPSON RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Aug. 26, 1926 frcquancy Selective Relay INVENTOR Patented Nov. 20, 1928.

UNITED STATES HOWARD A: THOMPSON, OF EDGEWOOD BOROUGH, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY,

CORPORATION OF PENNSYLVANIA.

OF SVVISSVALE, PENNSYLVANIA, A

RAIL\VAYTBAFFIC-CONTBOLLING APPARATUS.

Application filed August 26, 1926. SeriaiNo. 131,626,

My invention relates to railway traflic controlling apparatus, and particularly to appa-" ratus in which train carried governing means is controlled by energy received from the trackway.

In one arrangement of apparatus of the type mentioned it has been suggested to employ the usual track circuit current, that is, the current which energizes the track relay, for controlling the train carried governing means. In such apparatus control is effected by this current by means of receiving appliances at the front end of the train. lVhen this is done, it is obvious that the source of track circuit current mustalways be connected across the rails ahead of a train.

In the case of a double track railway in which the traffic on each track normally moves in one direction only, this requirement is easily met in the case of train movements in the normal direction, because a source of track circuit current for each section of track is then connect-ed across the rails adjacent the exit end of each section in accordance with standard practice in automatic block signals. In the case of single track roads, however, it is necessary for trains to proceed over the track in both directions, and in such instances with only the trackway apparatus thus mentioned, trains moving in one direction would not receive track circuit current. One fea ture of my invention is the provision of means located in the trackway for connecting a source of track circuit current across the rails at either end of each section, thus permitting train movement in both directions over a single track.

I will describe two forms of trackway apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a diagrammatic view of one form of trackway apparatus embodying my invention. Fig. 2 is a diagrammatic view of a modified form of trackway apparatus also embodying my invention.

Similar reference characters refer to similar parts in each of the views.

Referring to Fig. 1 the reference characters 1 and 1 designate the track rails of a stretch of railway tlackover which traffic normally moves in both directions. The track rails are divided into sections by means of insulated joints 2, only one of such sections AB being shown. Connected to the track rails near the exit end of the section is a transformer T, the primary 4 of which is constantly supplied with alternating current from line wires 5 and 5 which are supplied with current from a suitable source, here shown as an alternator K. Between the secondary?) and the rail 1 is connectedan impedance device 8 for the purpose of limiting the current in the secondary 3 when the rails 1 and 1 are short circuited by the presence of a train in the section. Also connected in series with the secondary 3 is a track-battery 6, and a resistor 7 for the purpose of limiting the flow of current from the batterywhen a trainoccupiesthe section.

A second transformer X has a secondary 9 which is connected to the rails through a resistor 10 and an impedance device 11 in a manner similar to that just described with reference to the transformer T-. The device 11 serves to counteract the effect of resistor 10 and to displace thephase of the current for operating the train carried apparatus and the resistor 10 is for a purpose which will appear hereinafter.

Each section is also provided with a track relay R having two windings, one of which is constantly supplied with alternating current from line wires 5 and 5*,- through wires 16 and 17 and the otherof which, W, is normally supplied with current from the track rails. The relay R is so constructed that when its two windings are supplied with currents of proper relative polarity the relay picks up, but if the current in either of the windings is reversed, the back contacts of the relay remain closed. The pick-up circuit for the relay R is from track rail 1, through wire 15, winding W of relay R, wire 22, front contact 23 of relay Z, and wires 24,20 and 21 to rail 1. This circuit is closed only when relay Z is energized. The relay R also has a hold- 1 ing circuit from track rail 1 through wire 15, winding W of relay R, wire 18, front contact 19 of relay B, through wires 20 and 21 to track rail 1*. This circuit is closed only when the trackrelay R is energized. The relay R also has a back contact 27 which controls the circuit for reset relay Z which is slow acting and is responsive only to direct current. When a train enters the section AB so as to shunt the relay R and cause it to close its back conbattery 6, through rail 1*, wire 21, winding of i-relay Z, wires 25-and 26, back contact 2? of 5 relayR, wires 28 and 15, track rail Limpedance device 8, secondary 3 of transformer T, and resistor 7 back to battery. Nhen the train vacates section AB and ceases to shunt relay Z it becomes energized and this circuit 10 closes the pick-up circuit for winding W of track relay B through a front contact 23 of relay Z.

When atrain enters the section AB, moving from right to left it is necessary that train controlling current be supplied to the left hand end of the section. 'For this purpose I "provide the transformer X having a primary '31'which is energized from line wires 5 and 5 only when relays Sand Zare tie-energized. "The circuit for the primary 31 is from line Wire 5," through wires 16 and. 29, back contact v: 30 of relay Z, primary 31 of'transformer X, wire .32, back contact 33 of relay R, wire 34:, back contact 35'ofrelay S and wire 36 back to linewire 5. This circuit is closed when the relaysR and Z are de-energized and the relay 'Sis also de-energized. The relay S is'the stick relay well known in absolutepermissive block. signaling systems, and'its'control is well understood insuch systems, so that it will merely be necessary to state that this relay is normally ole-energized and becomes energized .only'when a train moving from left to right enters the section AB. It will now be clear that current is supplied to the track rails 1 and 1 from the transformer X only when a train moving from right to left enters the section A-B.

The! operation of the apparatus is as follows \Vhen the track section AB is unoccupiedthe' parts will assume the positions shown in the .drawing. Under these conditions falternating'current is supplied from the track transformer T to the track rails of the section causing the winding \V of. relay R to remain energized, the other element of the relay B being energized from the line. wires 5 and 5 *When a train moving from left to right passes point A, relay' R will be shunted and will open its own connection to'thetrack rails 1 :and 1 by opening its contact 19. De-energization of 'the.relay R willclose contact 33 but the circuit for primary 31 of transformer X williemain open at theback contact 35 'of the stick relay Swhich is energized as soon as the train enters the section. Back contact 27 of relay :R is also closed butxno-currentfrom battery 6; will besupplied to the relay Z because the battery 6 is shunted by the wheelsand axles of the train. As soon as the'train passe-sthe .point B' the .battery 6 feeding current in 'serieswith' the secondary 3 of track transformerT will momentarily energize the reset relayZ'closing its front contact 23, and com- 55 pleting'the pick-up circuit-forthe relay R occupies the section.

which then closes its front contact 19 to'estab lish the holding circuit for this relay. Energization of relay R also opens the contact 27 and causes relay Z to be ole-energized; i The 31 of transformer X will be closed, so that alternating current is supplied to the left hand end of the section as long as the train The current fed by transformer X is of reverse relative polarity as'compared with the energy normally fed by transformer T, so that energy from transformerX which is connected to winding Wof relay it tends to hold this relay down and to hold its back contacts closed. "When the train vacates section A-B, directcurrent from battery 6 again energizes relay Zwhich first cuts off the supply of energy of reverse r'elative polarity from transformer X and then allows energy of normal relative polarity from transformer T to. energize relay It.

hen the relay R becomes energized itopens the circuit for the primary 31 of transformer X at contact 33, so that the supply of energy to the left hand end of the section is discontinued. Energization of relay R'also opens long enough to allow the relayB to establish its holding circuit.

The apparatus shown in Fig. 2'is similar to that in Fig. 1 except that the reset relayin this case is responsive to alternating'current so that no source of direct current is necessary. V V

Referring now to Fig. 2 alternating'current'is normally supplied to the track rails 1 and 1 from the secondary 37 of a track transformer L, the primary 38 of which is supplied withcurrent'from line wires 5 and 5 An impedance cevice 39 connected'inseries with the secondary 37 limits the flow of cur rent when a train occupies the section. Alternating current may also be supplied to'the section A- Bfrom a second track transformer P which is connected in' parallel with the transformer L. The primary-{t4 oftransformer P is at times supplied with current of twice the frequency of the source K, through a full-wave rectifier N which is supplied with currentfrom the line wires 5 and 5over a back contact 45 of a line relay H.

The relay H is the'standard home relay of de-energized when a train enters the section AB moving from right to left, and also becomes de-energized as soon as a train moving from left to right leaves the next passing siding to the left of the section AB. It will be clear that the transformer P can supply double frequency current to the section only when the relay His Clo-energized.

Current may also at times be supplied to the section A-B from a track transformer M, under conditions which will be described hereinafter. The relay R- is similar to that shown in Fig. 1 and has a pick-up circuit which is from track rail 1 through wires 46, 51 and 55, front contact 56 of relay F, wire 49, winding IV of relay It, and wire to track rail 1. The relay R also has a holding. circuit which is from track rail 1 through wires 4c6and 47, front contact 18 of relay R, wire 49, winding W of relay R and Wire 50 to track rail 1 Relay R is normally supplied with alternating current from the track transformer L. The reset relay in this form of apparatus is of the frequency selective type and is designated by the reference character F. This relay is not responsive to alternating current of the frequency supplied from line wires 5 and 5% but it is responsive to current of twice that frequency. This relay has a winding Q which is controlled by the back contact 53 of relay R so that thiswinding is energized only when relay It is ole-energized and double frequency current is being supplied to the track rails 1 and 1 from the transformer P.

The primary of transformer M is at times supplied with alternating current of the frequency of alternator K, from line Wire 5 over wire 57, back contact 58 of relay R, wire 59, primary 60 of transformer M, and wires 61 and 62 to line wire 5. This circuit is closed only when relay R is ole-energized. The back contact 58 of relay R also controls the supply of double frequency current to one winding of reset relay F over a circuit from line wire 5*, wire 57, back contact 58 of relay It, rectifier 0, wire 63, winding of relayF, wire 64, rectifier O, and wires 65 and 62 to line wire 5. This circuit is closed only when the relay R is ale-energized due to the presence of a train in the section AB.

The operation of the trackway apparatus shown in Fig. 2 is as follows: Winding IV of relay R is normally supplied With alternating current of the frequency supplied by alternator K from the track transformer L. hen a train moving from left to right enters the section AB the relay R becomes cleenergized opening its front contact 48 and closing its back contacts 53 and 58. The relay I-I having been. de-energized when the train left the passing siding to the left of the section A-P), the contact 45 is closed so that double frequency alternating current is supplied to the track rails 1 and 1 from the secondary 42 of transformer P, but since the track rails are shunted by the wheels and axles of the train, no current is supplied to the left .end of the section hence the reset relay F remains de-energlzed. WVhen the train leaves fore closes its front contact 18 and completes its holding circuit. lVhen the relay R is energized the contact 53 opens to cause deenergization of the relay F, and relay I-I again picks up discontinuing the supply of double frequency current to the right hand end of the section and restoring the parts to their normal positions as shownin the drawmg. I

When a train moving from right to left enters the section A-B, the relay R is shunted to close the contact 58 and supply the track rails 1 and 1 with current of the frequency of alternator K and of reverse polarity compared with the energy fed by transformer L. The presence of the train in the section causes'the transformers L and P to be shunted so that they supply no alternating current to the left hand end of the section. WVhen a train, in leaving the section, passes the point A, double frequency current is sup plied to the section from the transformer P and this energizes the Winding Q, of reset relay F which then picks up and completes the pick-up circuit for relay B. When relay R becomes energized the supply of alternating current to primary 60 of transformer M is interrupted by the opening of the contact 58 of relay R and the opening of contact 53 of relay R causes de-energization of winding Q, of relay F so that the parts are restored to their normal positions.

It will now be seen that I have provided a means for reversing the track circuits for single track operation which requires few operating parts, and since the parts are approach controlled, the consumption of, current will not be excessive.

Although I have here-in shown and described only two forms of trackway apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spiritand scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a section of railway tion'only for supplyingcurrent to the relay end of the section only when both of said relays are de-energized.

2. In combination, 'a' section of railway track, a source of alternating current" and a source of direct current constantly connected With one end of the section, an alternating current track relay connected With the other end ofthe section, adirect current relay for controlling thetrack relay, and a, second source ofalternating current for supplying current to the relay end of the section only when 'both'of said relays are de-energized.

8. :[11 combination, a section of railway nected With one end'of the section, an alternating current'relay normally connected with the other end of the section, a direct current relay for controlling the alternating current relay, and asecond sourceof alternatingcurrentcontrolled byt'raflic 1n one direction only 'i orsupplying ct'i'r'rent to the relay endof the sectionwvhen both of said relays are de-en'er- 'gized.

4. In combination, 'avsection of' railWay track, a-"source 0t alternating current connected' W1th one end of the section, an alternating current track relay connected With the other'end 0t the'section, another source of current, a relay responsive only' to "current from the other source and for controlling the track relay anda second source of alternating HOWARD A. THOMPSOW. 

